In the year 1999, animation stuidio TOEI created Digimon Adventure - and probably didn't really believe that it was going to be a huge hit themselves. After all, Pocket Monster (Pokemon) was a huge competitor, since this show was already there for about 3 years and it's creators were about to release the first Pokemon movie. Still, Digimon became a huge hit and was successful worldwide. By now, there are several Digimon seasons and movies.

FOX Entertainment bought the rights to distribute the series in the USA. When they were about to release the Digimon movie, no one could have known that they bought the rights of the first three Digimon movies which they then cut together to release it as one single movie. They completely ignored the fact that the third movie was based on events that took place in the series "Digimon 02" and therefore had nothing to do with the first 2 movies. Instead they used the dubbing as well as the postponement of several scenes to connect the movies together. In fact, the first "movie" which is only 20 minutes long could rather be seen as a bonus episode than a real movie. Chronologically it takes place before the first season "Digimon Adventure". Therefore it makes sense that each movie always contains characters of the seasons they're connected to. For the final movie, the US producers deleted all the new characters from the third movie - along with a complete subplot.
The US version of the series was always edited/censored since the series was not child friendly enough for the US censors.

The alterations are extremely severe, so let's have a look at each movie seperately.

Digimon Adventure. The first movie is only 20 minutes long so it's hardly longer than a regular episode. You see Kari's, Tai's and Agumon's (who in the first season belongs with Tai) first encounter. In the first night there's an electronic anomaly and a huge Digimon attacks the city, however, Agumon defeats the enemy. The story is not that complex and you also don't really find out where the evil Digimon came from. The movie shows a few scenes that shine a light on Tai's and Kari's family life. Especially those scenes that take place before Agumon has digivolved are rather funny. At this point, the Digimons look a little different than they do in the series later on. In the series they always are just as intelligent as human beings and are able to communicate with them. In this movie, however, they rather seem to be like animals - they can't speak and most of the time rather act through instincts than real intelligence.
Even though they cut away parts of the character and story development (the movie's target audience - kids - would probably have enjoyed the pursuit of the little Digimon in the apartment), the censorship is not too troublesome. Unfortunately they also cut away the explanation to why Tai is so close to Agumon later in the series. The battle itself was only slightly edited and even though there are a few cuts, the story of the movie stays the same.

Boku no wargame - Our Wargame The second Digimon movie was a little more serious. Similarly to the movie "WarGames" an evil Virus-Digimon hacks into several government's computers to launch nuclear missiles. The Digimons have to use the internet to fight the virus while t "Digiknights" in the real world try to avoid the crisis as good as possible.
For the US version they cut out the subplot with Matt and his little brother T.K. who currently are on vacation and hardly can ever connect to the internet. A huge part of this subplot was just cut out while most of the action scenes were not edited at all. Again, most of the story is still there despite the cuts.

It's a common thing for the US to edit Digimon that the editors added new dialogues to e.g. make a scene more funny. However, they really edited the dialogues immensely for the movie. The cut of the scenes is awful and often results in inconsitencies. If you look at the scene of the third movie where Mimi disappeared, there's a dialogue where they used several scenes of a dialogue which follows later on (it's a scene where T.K. and Kari talk to each other). In this added scene Patamon sits on T.K.'s shoulder while in the original scene he just holds him in his hands. This results in a chain of scenes where Patamon at first sits on the shoulder, then suddenly is held and then "jumps" back on the shoulders again.
Additionally, the picture quality is awful, too. The color saturation was reduced (most noticeable in the third movie). Also, they zoomed the image so that about a third of the frame (!) is lost. Here are a few examples (the images on the left represent the US DVD and the images on the right represent the Japanese versions):

There doesn't seem to be any explanation to why they zoomed the image so heavily. Not only doesn't it make any sense but there are also scenes (e.g. close-up shots of faces) where the effect looks downright weird.
Please excuse the extremely bad image quality of the thrid movie, but the only source for this movie was an old VHS tape. Anyone should be quite familiar with the "quality" of VHS tapes.

The soundtrack was completely changed as well - the original music is all gone. Instead you hear English Rock/Pop songs or other new music creations. The same thing also happened for the US version of the TV series (amongst anime fans the English song that is played during the evolution of the Digimon is said to be the worst replacement ever and the US version of Digimon in general is famous for it's bad soundtrack). Due to the alternative soundtrack a lot of scenes have an entirely different mood.

Interestingly enough, most of the cuts don't seem to be made due to censorship but rather to trim the movie down to a more appealing runtime. There are only very few cuts that seem to be cuts due to censorship and the harshest ones (e.g. the close-up shot of the split of Diablomon's head) still made it into the US version. If you consider the fact that the movie is only 84 minutes long while most of the children's movies are 90 to 100 minutes long, they really didn't have to cut away that much. Runtime of Movie 1 (uncut): 0:20:11
Runtime of Movie 2 (uncut): 0:40:50
Runtime of Movie 3 (uncut): 1:04:34

0:00:10The US version added a short sequence which is accompanied by a longer version of the Digimon rap (one of the replacements for the original score in the US version [also the series]). During the credits you see a CG animation while characters of the series fly through the image.

+ 60 seconds

0:00:17Tai is standing in the middle of nowhere. He tells us that it was a few years ago that he first saw a digital monster.

8 seconds

0:00:29Another shot of Tai - he smiles. Then follows the logo of the movie (which was simply called "Digimon Adventure", just as the season it refers to).

10 seconds

0:00:39In the US version they added a short scene. You see a few scenes from New York and from off screen you hear Kari's voice. She tells us that her name is Kari and that she's a part of a group called the DigiDestined. At first there were only a few members in their group but now several persons joined them.

Then you see a picture of her with T.K. (Kari tells us that it is her and another member of the DigiDestined) followed by a shot of Willis (who is also introduced by Kari - we get to know that he's from America) taking care of his Digimon.

Kari tells us that while every one of them in Japan only owned one Digimon, Willis got twins. She also tells us that while they had several teammembers they could rely on, Willis didn't have any human friends but only his Digimon.

Difference in time is dropped since this scene is from the third movie.

0:01:16Tai is standing in front of the bathroom door a little longer.
For the US version they deleted the Japanese credits.

1 second

0:01:25Tai goes to the door and looks into the room - the door is ajar.

Tai: "Dad?"

5 seconds

0:01:55A black screen which serves as a scene transition (originally you hear Tai's mother screaming from off screen) was cut out.

2 seconds

0:02:28You see Tai preparing a fried egg. He asks why his counterpart doesn't let the thing go because he thinks it might annoy the person.

3 seconds

0:03:13The DigiEgg rolls under the coffee table and Kari can't catch it. Finally it rolls out of the living room and Kari follows it, almost knocking Tai over.

Tai: "What...?!"

15 seconds

0:04:04Tai and Kari look at the Digimon a little longer.

3 seconds

0:04:26Kari uses her whistle and as a result the Digimon spits bubbles. This is repeated a few times.

7 seconds

0:04:48You see the bubbles flying through the city. From off screen you hear Tai asking what kind of a thing this might be.

6 seconds

0:04:55You see a board with Japanese letters on it. From off screen you hear Tai saying that it came from an egg, therefore it could be a bird.

4 seconds

0:06:38The cat and Koromon fight, causing a complete chaos in the room they're in. At the end, the cat forces Koromon into a corner and gets ready to attack it.

31 seconds

0:07:16The cat scratches Tai.

No time difference since the scene was implemented shortly after that in the US-version

0:07:19Instead of showing the actual scene of how two more scratches appear, the scene from the cut just before was edited in.

No time difference

0:07:48Tai is standing a little longer at the door, asking what Koromon was supposed to be. He asks if his sister gave it a name – Koromon introduces itself from offscreen.

8 seconds

0:09:12You can see some children wondering about the eletronic jams. A view of Tai is shown subsequently.

Tai: "K... Koromon?"

9 seconds

0:09:26You can see an elevator go up, Tai's and Kari's parents get out.

0:09:47Tai's father steps into the aparatment, calling out that he has returned home.

2 seconds

0:09:59

You can see Tai's, obviously drunk, father taking off his shoes and already being expected by his wife, telling him to be a little quieter when returning home. She then asks him if he knew what time it was, but he ignores her and shouts out his children's names.

Only now is it that Tai realizes his father just returned home. He is already on his way to his children's room, where his wife is trying to stop him, she doesn't want him to wake up the children. The father wants a good night kiss, but Tai keeps the door closed from the inside, he cannot open it.

16 seconds

0:10:18Tai's father continues trying to open the door, his wife tells him to stop and accuses him for being like that every night.

Through the door's glass you can see the parents go away.

10 seconds

0:10:33Agumon is held back by the wall before breaking through it.

1 second

0:11:12A short close-up of Agumon and Kari has been removed.

2 seconds

0:11:45Agumon has a car pass by before continuing to walk on the street.

2 seconds

0:11:52Agumon takes a few steps back. Kari, calling it Koromon, asks if it wouldn't talk to her any more.

8 seconds

0:12:20You can see heavily breathing Tai.

2 seconds

0:12:49You can see Tai standing on a bridge, gasping. He notices Agumon's fireballs in the distance, then continues running.

In the meantime, Agumon has chased the airplane's lights, but loses them. Kari proposes going home.

Agumon looks back, grumbling, you can see a blinking light.
20 seconds

0:13:12The TV set only shows white noise.

1 second

0:13:15You can see children looking out the window in two more shots.

2 seconds

0:13:23The anomaly in the sky is shown longer.

1 second

0:13:26Ditto.

3 seconds

0:13:33Here again.

5 seconds

0:13:41Agumon runs down some steps.

3 seconds

0:13:59You can see Tai running (the US-version only starts as he has already passed under the bridge).

2 seconds

0:14:15The bird-digimon is hit by a fireball. You can see Kari and Agumon, Kari calls out its name.

Tai comes running to them.

6 seconds

0:14:48You can see the damaged bridge from a great distance.

4 seconds

0:14:53Again, the children are shown, watching the spectacle.

4 seconds

0:15:07You can see the house in which all the lights go haywire. A short view of Agumon in the dust cloud follows, two children in their apartment are looking out of the window.

10 seconds

0:15:58A few feathers drop to the ground.

1 second

P L A T Z H A L T E R

0:16:10The opening credits of Film #2 are missing as well.
The Japanese Version starts with a text box, then the Digimon egg again plus the news "Hello".
The US Version lacks the text box and starts with the egg and the message at once. Then the above-mentioned scene the actual movie starts with. The scenes from the credits remain unchanged but the text boxes, that interrupt the credits and show the names of the people involved, are missing. Actually the credits ar being accompanied by the Japanese Opening of the TV series "Butterfly". The length of that has been added up instead of listing the length of each single text box.

45 sec

0:16:35The text in the close-up of Tai's computer got translated. While he changes the word "From" to "Love" in the US Version, he corrects his name in the Japanese Version. When he gets startled by Kari, he accidentally puts a heart behind his name.

Missing part:

Modification of the farewell:

3 sec

0:17:01Kari is lacing her shoes in the hallway when her mother comes home.
The mother asks if she wanted to go out, she agrees. The mother tells her to be careful, Kari replies she would.

The beginning of the following shot has also been removed: the screen of Tai's computer inform him about the denied reception of the mail to Sora. In the US Version, he realizes that while he's sending the mail.

10 sec

0:17:34Translated inscription on the heart.

no difference

0:19:09Translated mail.

no difference

0:19:10Missing zoom to the mail.

2 sec

0:19:20The shot of Digimon eating data zooms much more out.

Izzy says from the off it was a baby at that moment, but when it started growing it was going to eat data from the entire network.
Tai, also from the off, wants to know what was going to happen then.
Izzy, still offscrreen, replies that worldwide, computers weren't going to function anymore if that happened.
Tai says from the off that was bad.

12 sec

0:19:35Shot of a furter supermarket. A woman goes through the entire assortment and finds a pretty high price label (1 mil yen). Believing she just got a wrong-ticketted product, she reaches for another one but the price of it it quite high as well. Shot of the barcode for a couple of seconds, then a freeze frame of the checkout counter with lots of complaining people. They're upset about the high-priced assortment.

18 sec

0:20:42Extended shot of Taichi and Izzy in front of the computer.

5 sec

0:21:29Slightly shortened conversation with Gennai.

Gennai says from the off it was going to have serious consequences if they didn't intervene. Izzy agrees and wants to know how they could be defeated.

10 sec

0:22:12Shot of running Joe in the room where the acceptance test takes place.

5 sec

0:22:58Extended shot of Tai.

2 sec

0:24:56Shot of a giant wheel. A scared girl is in one of the baskets, the two guys with her don't give a damn. When the giant wheel starts spinning faster and faster, the two guys get scared while the girl starts laughing. Tai's mom sees everything through the window. She screams Tai's name.

17 sec

0:25:43Another translated mail.

no difference

0:28:28After the first fight, Izzy gets mails from all over the world because anyone had the opportunity to watch it on their computers. In the Japanese Version, he gets two mails from some strangers. The first one is a boy from Australia who just says about the fight it was the first time ever he'd seen a digimon. Izzy is surprised he could see the fight. The second mail has been sent from a girl in Singapur. She wants to know if they were really that weak because they'd lost a fight in majority (2 vs 1). Then they become aware they also have a mail from the digimon. In the US Version, they get a mail from Willis instead. Willis says he was sorry and it had been his fault. He adds they should try to find a way to delay it. Subsequently a mail from Infemon, which has been translated in the US Version.

9 sec

0:28:48Shot of Kari at her friend's birthday party. She doesn't like Kari's being on the phone again because she (Kari) disrupts the card game. Kari explains she couldn't get home because she was winning.

18 sec

0:29:37The shot of the Infemon ends earlier.
Tai asks from the off what to do and adds they couldn't reach the others if the phones malfunctioned.

3 sec

0:30:13Extended shot of Matt on the phone.

2 sec

0:30:51Further shot of the city while Tai is calling his friends with the emergency call system.
Tai (from the off) wants Joey to pick up if he was there.

4 sec

0:30:59The name on the plate has been changed from "Yagami" to "Kamiya". "Kamiya" is the last name of Tai's family in the US Version.

no difference

0:31:19Translation of Mimi's postcard.

no difference

0:31:31Shortened shot of Tai.

2 sec

0:32:47Tai and Izzy on the phone. They receive a further message from Matt and T.K.
T.K. says they had their digivces but grandma didn't have a computer. Matt replies he didn't believe there even was a Shimane. Tai is flabbergasted and faints. She swears and says they were screwed. Izzy tells them to get to a computer asap.

22 sec

0:33:02Infemon's mail has been translated again and a previous message to inform about a new mail has been deleted as well.

no difference

0:33:06The following is completely missing. Matt and T.K. ask for a computer in the entire village. The first citizen tells them his computer had just gone down. Then they find two home where they residents don't even know what a computer is. Then a shot of them strolling across a street. Matt determines there was no way to get a computer in Shimane. They finally reach an office with a computer in it. The woman in the office explains she was sorry but the computer dodn't have an internet connection. T.K. is close to tears. The man in the office tells the woman to just let them use the computer. She asks him if he didn't have to get some supplies done. He replies he was sorry for her. Then she repeats the computer didn't have an internet connection. The man tells her to connect it to the internet then. She says his name but Matt barges in. He doesn't them to fight.

38 sec

0:38:52Shortened shot of Izzy and Tai.

2 sec

0:39:25An airplane is flying in the sky.

3 seconds

0:39:27As usual, Diabolomon's e-mail was translated.

No time difference

0:39:33There was a short view of the room implemented here in the US-version.

+2 seconds

0:39:51In the US-version, Willis tells Izzy that the US has launched nuclear missiles, in the Japanese version, it is some student from Taiwan who hacked himself into the Pentagon. The e-mail's images were edited again, too, and the text was translated again. Instead that, like in the original version, the camera zooms out constantly, there is a close-up shot of the e-mail shown in the US-version. This is just a recycled still image from earlier, only the text was changed.

No time difference

0:40:09Another airplane is shown flying in the sky.

3 seconds

0:40:18Izzy reads more data about the missile. It has a range of 20.000 Kilometers and can reach almost any point on the planet. The maximum speed is 15.000 miles per hour.

5 seconds

0:40:32Offscreen, an old man notices the weather is turning worse. His wife agrees and says she should probably get the laundry.
She asks her husband to bring Matt and T.K. To Kinu-san, as they were with Yasuko.

The two only stare at the computer, dumbfoundedly. The old woman asks if they had heard what she had said.

18 seconds

0:40:43There were othere scenes used here. An airplane in the sky is shown in the US-version, a scene recycled from earlier in the film. Here, Izzy comes up with the idea that the original Diabolomon has to be defeated to make the clones disappear.

Duration: 10 seconds

There is another shot of the room in the Japanese version.
Izzy says that the missile will only explode if somebody activates the detonator, and if this is a game, then only one of them could have the clock.

Again, the e-mail of Diabolomon is shown in which he asks "Which one has the clock?"
(Background is that Diabolomon asks "Which one has the clock" in the Japanese version as it has it disappear from his hands. In the US-version he says "Back to the beginning".)

Izzy says that if they are able to defeat the one that has the clock, the missile should not explode. Tai asks him how they could find that one and Izzy says that they will have to take out every single one of them.

Duration: 17 seconds

0:48:50The scenes were swapped here. While in the Japanese version you first see scenes from everywhere in the world (Tai's mother e.g. failed at making a cake) before Diabolomon's head is split, the US-version shows the splitting directly.